1. Field of the Invention
This invention relates to electric power distribution systems and more particularly to meter centers in which power delivered to multiple users is separately metered. Specifically, it relates to the electrical connections between the supply and tenant bus bars in the meter center and the meters.
2. Background Information
Meter centers are used for metering electric power delivered to multiple tenants from a common feeder system. Typically, the meter center includes an upright cabinet forming an enclosure divided into side-by-side meter and disconnect switch compartments. Feeder buses, typically three phase buses and a neutral connected to the utility lines, extend horizontally through the rear of the cabinet. The meter compartment has a pair of vertical supply buses connected to a selected pair of the feeder phase buses by phase balancers, so named because connections can be made to selected phases to generally balance the feeder bus phase currents. The vertical or supply buses can include a neutral bus if the meters have a neutral connection.
A pair of tenant buses for each metered circuit extends horizontally from the disconnect switch compartment into the meter compartment. A meter socket mounts a meter in the meter compartment for each tenant circuit and electrically connects the meter to the supply buses and the tenant buses. Commonly used electrical connections on the meter socket include single ended plug-in jaws which are engaged by stabs on the meter. The connectors which incorporate the plug-in jaws are bolted to the socket plate and to either a supply bus or a tenant bus. The four power conducting connectors have a total of about 20 bolted connections in the current path. Such connections require labor to complete and are subject to heating if they become loose. Providing adequate standoff clearance between, and routing for, the closely spaced orthogonally oriented vertical and tenant buses presents additional challenges in the design of meter centers. Furthermore, proper support must be provided for the socket and the buses to withstand the forces applied during installation and removal of the meter, particularly to prevent shorting of the bus bars.
There is a particular need for fastenerless jaws of a single configuration for connecting the meter to both the supply buses and the tenant buses.
There is a further need for such fastenerless jaws which have a minimal part count and are easy to manufacture and assemble.
There is an additional need for such fastenerless jaws which also do not require fasteners for mounting.
There is yet another need for such fastenerless jaws which provide improved electrical contact, and therefore, reduce contact heating.